Device for detecting deterioration of oil

Abstract

A device for detecting deterioration degree of oil is composed of an electrode unit in a cylindrical coil shape and a detector circuit connected to the electrode unit. The electrode unit is composed of a first electrode plate and a second electrode plate, both wound in a coil shape with an insulating layer disposed therebetween. The electrode unit is dipped in oil, and a potential difference between the electrode plates is measured by the detector circuit. The oil deterioration degree is detected based on the potential difference that varies according to a pH level of the oil. A distance between the first and the second electrode plates is kept small and precise to enhance accuracy in detecting oil deterioration without making the detector size large.

1 . A device for detecting deterioration of oil, the device comprising: 
 a first electrode plate;    a second electrode plate disposed to face the first electrode plate and insulated from the first electrode plate, both electrode plates being wound in a cylindrical coil shape; and    a detector circuit for detecting an electric potential difference between the first electrode plate and the second electrode plate when both electrode plates are dipped in oil.    
   
   
       2 . The detecting device as in  claim 1 , wherein: 
 an insulating layer is disposed between the first electrode plate and the second electrode plate.    
   
   
       3 . The detecting device as in  claim 2 , wherein: 
 the insulating layer is wound in a cylindrical coil shape together with the first and the second electrode plates, forming an electrode unit.    
   
   
       4 . The detecting device as in  claim 3 , wherein: 
 the insulating layer is formed in plural stripes that are discretely positioned between the first and the second electrode plates.    
   
   
       5 . The detecting device as in  claim 4 , wherein: 
 the stripes of the insulating layer are positioned along a circumferential direction of the electrode unit.    
   
   
       6 . The detecting device as in  claim 4 , wherein: 
 the stripes of the insulating layer are positioned along an axial direction of the electrode unit.    
   
   
       7 . The detecting device as in  claim 4 , wherein: 
 the stripes of the insulating layer are positioned along both a circumferential direction and an axial direction of the electrode unit.    
   
   
       8 . The detecting device as in  claim 3 , wherein: 
 the insulating layer is made of composite fibers through which the oil permeates.    
   
   
       9 . The detecting device as in  claim 3 , wherein: 
 the insulating layer is made of a porous resin material through which the oil permeates.    
   
   
       10 . The detecting device as in  claim 3 , wherein: 
 a plurality of holes are formed in the insulating layer.    
   
   
       11 . The detecting device as in  claim 3 , wherein: 
 the insulating layer is made of resin which is molded together with either the first electrode plate or the second electrode plate.    
   
   
       12 . The detecting device as in  claim 1 , wherein: 
 through-holes are formed in the first and the second electrode plates, and the through-holes in the first electrode plate are positioned to substantially face the through-holes in the second electrode plate.    
   
   
       13 . The detecting device as in  claim 1 , wherein: 
 one axial end of the first and the second electrode plates wound in a cylindrical coil shape is connected to an electrode holder.    
   
   
       14 . A method of manufacturing the detecting device defined in  claim 3 , the method comprising: 
 winding the first electrode plate and the second electrode plate in a cylindrical coil shape together with the insulating layer disposed between the first and the second electrode plates, thereby forming an electrode unit;    coupling a cap to one axial end of the electrode unit to thereby maintain a shape of the axial end; and    connecting an electrode holder having connecting terminals to the other axial end of the electrode unit.